Testing and rejecting apparatus for vacuum packed cans



G. L. HURST Feb. 9, 1960 TESTING AND REJECTING APPARATUS FOR VACUUMPACKED CANS Filed Oct. 12 1953 2' Sheets-Sheet 1 INVENTOR.

Feb. 9, 1960 v G. L. HURST 2,924,093

TESTING AND REJECTING APPARATUS FOR VACUUM PACKED CANS v f-| -a I 4 /7/2 F/7 i i E i i INVENTOR. r 650/965 1. H0957 M, 77 fit 1&7

@ l 147 TOR/V15 f5 United States Patent TESTING AND REJECTING APPARATUSFOR VACUUM PACKED CANS George L. Hurst, Redwood City, Calif.

Application October 12, 1953, Serial No. 385,356

7 Claims. (Cl. 7345.4)

This invention relates to apparatus for testing the degree of vacuum invacuum packed cans, such as coffee cans, and rejecting cans in which thedegree of vacuum as to cause such tops to deflect outwardly. The amountof such deflection is, of course, inversely proportional to the degreeof vacuum in the can. Means responsive to the amount of such deflection,is generally provided for operating a rejecting arm or plunger so as topositively push a rejected can off the normal path of travel and into achute or some other conveyor means which conveys the rejected cans toanother station.

To produce a suction externally on the cans, it is necessary to providea suction head movable with the can conveyor and adapted to make an airtight seal with the top peripheral rim of the can. Obviously, themeasurement of the deflection of the can top must be made while thesuction head is in air tight engagement with the can, therefore therejecting operation by which the can is removed from the can conveyorcannot be performed until the can is released from the suction head.

The generally adopted method is to save the deflection reading byproviding a deflection responsive means for each can and a separateelectrical circuit for each deflection responsive means and whichcircuits are adapted to close when a dcfectively packed can is engaged.However, inasmuch as closing of the circuits energizes a solenoid toimpart the necessary motion to the ejecting plunger or arm, it isnecessary to save the deflection reading by a time delay device of somesort so that ejection always takes place at the same point in the pathof travel of the cans. At such point the can has already been releasedfrom the vacuum head.

Such a system leads to complications and the chances of an inaccuratetest are increased. Furthermore there are many electrical switches toget out of adjustment and the provision of the time delay obviouslyincreases the total cost of the installation.

In addition, to the above mentioned disadvantages, the use of apositively acting can ejecting arm or plunger slows down the testing andrejecting operation inasmuch as such arm or plunger must be withdrawnacross the path of travel of the cans before the next can arrives at theejection point.

The main object of the present invention is, therefore, the provision ofa vacuum packed can testing and rejecting apparatus which isconsiderably simpler in operation than those heretofore employed andwhich apparatus is cheaper to construct and more eificient in operationthan prior art apparatus of like nature.

Another object of the invention is the provision of an improved vacuumpacked can tester which requires only one simple electrical circuit andone switch.

Still another object of the invention is the provision of an improvedmechanism for ejecting defectively packed cans.

Other objects and advantages will be apparent from the followingspecification and drawings.

Fig. 1 is a top plan view of a can conveyor system showing the testingand rejecting means.

Fig. 2 is a side elevational view of the apparatus of Fig. 1 with aportion of the same broken away to show internal structure.

Fig. 3 is a greatly enlarged fragmentary vertical crosssectional viewthrough the apparatus of Fig. 1 as taken along lines 33 of that figureand showing the essential elements of the testing and rejecting means.

Fig. 4 is an enlarged side elevational view of the invention showing themeans for resetting the deflection gage elements, as seen along line 4-4of Fig. 1.

Fig. 5 is an enlarged semi-schematic plan view of the electromagnet andadjacent structure as taken along lines 55 of Fig. 3 and showing theoperation of the invention during ejection of a defectively packed can.

In the following description, the conventional apparatus will bedescribed briefly and only the invention claimed herein will beconsidered in detail.

The cans are fed to the testing conveyor by a rotary support 1 (Fig. .1)which, in combination with known devices, spaces the cans apart apredetermined distance so that one can is received by a revolving cansupport 2 of which twelve are shown in the drawings (Fig. 1). These cansupports 2 are respectively supported on vertically disposed elongatedmembers 3 (Fig. 2) which, in turn, are slidably received in bearings 4formed at spaced points around the periphery of a relatively largedished carrier 5. This carrier 5 is rotatably supported on a centralvertically extending stationary shaft 6 and is provided with an'internalgear 7 with which a pinion 8 meshes. Pinion 8 is fixed to the upper endof a vertical shaft 9 which in turn is rotatably supported in a hearingit The lower end of shaft 9 is provided with a bevel gear 11 which isdriven by another bevel gear 12 on shaft 13. Rotation of the dishedmember 5 is effected through a chain drive 14 between motor 15 and shaft13 (Figs. 1, 2).

The lower ends of the vertically disposed members 3 are provided withrollers 17 which engage a stationary circular cam track 18 designed tomove the cam supports 2 to any predetermined elevation during rotationof the carrier 5.

Rotation of the can supports 2 relative to carrier 5 is prevented byradially inwardly extending arms 19 rigidly secured to supports 2 andapertured at their inner ends to receive upwardly extending rods 20which in turn are rigidly secured at their lower ends to the uppersurface of the carrier 5.

Above the carrier 5 and supported for rotation about shaft 6 with saidcarrier is a horizontally extending top 22 which is provided on itsunder side with a plurality of suction heads generally designated 23(Fig. 3) and respectively adapted to be engaged by the cans 24 onsupports 2. The heads 23 are each provided with a downwardly openingannular groove 25 which receives an annular gasket 26 of resilientmaterial such as rubber (Fig. 3). Thus, as best seen in Fig. 3, uponupward movement of a can support 2 by the action of cam track 18 theupwardly directed peripheral rim 27 of can 24 is moved into air tightengagement with the gasket 26 to form a chamber 28 between the top 21 ofthe can 24 and the head 23 (Fig. 3).

Communicating with such chamber 28 through each head 23 is one end of aconduit 29. The conduits 29 for all of the heads 23 are connected attheir corresponding opposite ends to a conventional rotary valvemechanism positioned centrally of top 22 and including a stationaryvacuum chamber 30' secured at the inner end of a radially extending arm31. This arm 31 extends horizontally over the top 22 and is bentdownwardly at its outer end (Fig. 3) to provide a vertically extendingportion 32 which is stationarily secured to any suitable structure.

The vacuum chamber 30 is exhausted through a suction line 33 (Fig. 2)which is connected to any suitable source of vacuum (not shown) forapplying a predetermined suction.

Secured to top 22 is a valve head 34 (Fig. 2) which is provided with asuction port 35 and an exhaust port 3'6 (Fig. 1).

In operation, when the cans 24 are received on supports 2 (Fig. 1), thelatter are spaced downwardly from their corresponding suction heads 23.Upon rotation of the carrier 5 in a clockwise direction as indicated inFig. 1, the action of cam track 18 is such that the cans 24- are movedupwardly into air-tight engagement with the gasket 26 of head 23 asshown in dotted lines in Fig. 3.

At this point the conduits 29 connect with the suction port 35 and asuction is applied to the space 28 between the tops of the cans and theheads 23. After the upward deflection of the tops of the cans ismeasured (in a manner to be described) further rotation of the carrier 5connects the conduits 29 with the exhaust port 36 and the cans arethereby freed from their corresponding heads and are ready for furtherprocessing.

The structure above described is conventional and no claim is madethereto except in combination with the novel feature constituting thepresent invention and which features will now be described.

For the purpose of gaging the upward deflection of the tops 21 of cans24 when an external suction is applied thereto, I provide a verticallyextending central bore 40 through each suction head 23, the latter beingprovided with an upwardly extending boss 41 so that the upper end ofsaid boss is above and clear of the conduits 29 (Fig. 3).

Slidably received in bore 40 is an elongated pin 42 which is formed atits lower end with an enlarged head 43 having a downwardly directedconvex portion adapted to engage the tops 21 of cans 24 at a pointcentrally of the latter.

The upper end of pin 42 extends through the top of boss 41 and isthreaded to receive a bushing 44 which is flanged at one end to supporta disk-like element 45. A nut 46 screw-threadedly engages bushing 44 anddisk 45 for releasably locking the latter at various points along thelength of rod 42 as desired. An upwardly opening recess 47 is formed inboss 41 to permit downward movement of the bushing 44 with pin 42 fromthe position shown in Fig. 3 if required.

The pin 42 is preferably freely slidable in bore 40, but I provide meansfor adjustably varying the resistance to movement of pin 42 in bore 40.This comprises a ball 49 positioned in a radially outwardly opening holein boss 41 and a short compression spring 50 for urging the ball 49against pin 42. A screw 51 is received in the boss 41 so that rotationof the same permits varying the compression in spring 50 and thereforethe friction between ball 49 and the periphery of pin 42.

By the above described structure it will be apparent that the frictionon pin 42 may be adjusted so as to overcome the weight of pin 42 andalso cause said pin 42 to stay in any position to which it is moved.

Supported on the underside of arm 31 is a switch 52 which includes areciprocally mounted actuating pin 53 extending horizontally outwardlyof switch 52 and into the path of travel of the disks 45 carried by suchpins 42" that are man up position. With reference particu-- larly toFig. 3, it is seen that the normal outer position of actuating pin 53 ofswitch 52 is such that disk 45, when in the dotted line position,interferes with the outer end of pin 53 just enough to cause the pin 53to be urged inwardly of the switch to actuate the latter. The usualspring means (not shown) within the switch body urges the pin to itsouter position again after the disk passes.

The switch 52 controls a circuit, generally designated 54 (Fig. 1) whichincludes a source of electrical energy 55 and an electromagnet 56.

This electromagnet 56 comprises a pair of upper and lower parallel polepieces 57, 58 respectively (Fig. 3), core 5) and winding 60, the latterbeing in circuit 54 (Figs. 1, 3

Referring again to head 23 (Fig. 3), it is seen that when the conduit 29corresponding to the suction head 23 is connected through suction port35 to the source' of vacuum and the associated can 24 is in its upposition as shown in dotted lines in Fig. 3, the partial vacuum createdabove can 24 tends to cause the top 21 to deflect upwardly. If thevacuum in can 24 is below a predetermined minimum, the amount of suchdeflection will cause pin 42 to be moved upwardly so as to shift disk 45into the path of travel of actuating pin 53 on switch 52'. In thisconnection it will be understood that the thickness of disk 45 must besuch that the disk will engage pin 53 for any possible range ofdeflections indicating a defective vacuum. Obviously, the disk 45 mustbe adjustably positioned so that when the vacuum in the can is just lessthan the permissible amount, the disk 45 will actuate switch actuatingpin 53. In such a case the pin 53 will be engaged by disk 45 along theupper edge of the latter.

When the vacuum in can 24 is extremely poor the bottom of head 23 mayact as a stop for the can top 21 as shown in dot-dash lines in Fig. 3.In such an event the disk 45 will move to the position shown in dot-dashlines in Fig. 3.

By making the bore 40 in head 23 relatively long, the leakage of airbetween pin 42 and bore 40 may be minimized. However to prevent any suchleakage a conventional O-ring seal 62 may be provided on the bottom ofrecess 47 around pin 42 and such seal may be held against such bottom byspring clip 63. Such a seal will, of course, contribute at all times tothe friction opposing movement of pin 42.

The electromagnet 56 is stationarily positioned alongside the path oftravel of cans 24 and is mounted on a yoke 64 which, in turn, may befastened to the vertically extending portion 32 of arm 31 (Fig. 3).

The upper and lower pole pieces 57, 53 are identical and each comprisessubstantially a sector of a circular plate. As best seen in Fig. 5 theelectromagnet 56 is positioned with the pole pieces substantiallytangent to but slightly'spaced radially outwardly from the circularlocus of the outermost sides of cans 24 as the latter are moved in theircircular path of travel as above described.

In Fig. 5 a can 24 is shown by dot-dash lines in its normal position Aon can support 2 in which position it is seen that the can just clearsthe pole pieces of the magnet. The same can is shown in full line inposition B to which it is attracted when the'electromagnet 56 isenergized. Thus it will be seen that as said can comes to a position Aalongside electromagnet 56, and if the latter is deenergized, such canwill proceed along its normal circular path of travel and will finallybe removed by a conventional rotary device generally designated 65 (Fig.1).

However, if electromagnet 56 is deenergized when the can is in positionA, such can will be attracted to position B and will remain inengagement with the pole pieces, until the electromagne't isdeenergized.

Referring specifically to Fig. 5, it is seen that the continuousmovementof can supports-- 2 will cause the can to be urged along thecircular path of travel C of said supports but at the same time themagnetic attraction of the electromagnet 56 will hold the can to anarcuate path of travel D parallel to the peripheries of pole pieces 57,58.

Extending slantingly downwardly from the path of travel of can supports2 is a stationary reject chute 67 which is formed with an upper edge 68concentric with said path of travel. Chute 67 is positioned so that acan, shifted from its can support 2 will, when moving along the rejectpath of travel D, come to a position E at which it is partiallysupported on edge 68 of chute 67 and also on its support 2.

Upon further movement of the can support 2, it will be clear that thecan will move to a position E at which its center of gravity is past theupper edge 68 of a chute 67. If the electromagnet 56 is deenergized whenthe can is at position B it is obvious that such can will drop freely bygravity down chute 67. The apparatus by which the electromagnet 56 isenergized and deenergized will now be described in greater detail.

As best seen in Fig. l, the switch 52 is positioned so that the same isactuated, in the case of a defectively packed can, when such can isalongside electromagnet 56 or, more accurately, when such can is inposition A in Fig. 5.

I provide means for deenergizing the electromagnet 56 when the positionof the can support 2 is such that its corresponding can is at theposition of unbalance as indicated at E in Fig. 1. This means comprisesa conventional resetting pin 70 on switch 52 (Fig. 3) and an elongatedarm 71 which is swingably supported intermediate its ends on a pivot 72.One end of arm 71 is adapted to be engaged by disks 45 of suction heads23 when a rejected can is in position B.

As best seen in Fig. l the disks 45 swing the arm 71 about pivot 72causing the other end to depress resetting pin 70 thus breaking circuit54 and deenergizing electromagnet 56 thus preparing the same for actionon the next succeeding can if required.

It is important to note that the distance moved by the can supports 2between the time electromagnet 56 is energized is less than the spacingbetween adjacent supports. By the arrangement shown in Fig. 5, it isapparent that ample time remains between the release from electromagnet56 of a rejected can and the positioning of the next succeeding canalongside said electromagnet (position A).

It is emphasized at this point that no loss of time occurs which mightotherwise result if a plunger arm, or other positive rejection memberwere required to eject a can into chute 67. In such a case, it would benecessary to retract the ejecting means before the next succeeding canreaches the reject point. By the present invention, no such loss of timeis suffered.

The last step in the operation is to depress the pins 42 in heads 23 sothat the same are all in the full line position of Fig. 3 and ready tobe acted upon during the next revolution of carrier 5. This-isaccomplished by a stationary arm generally designated 73 which isfastened at one end to the large valve support arm 31 and is formedalong its length with a gradually downwardly extending lower surface 74which is adapted to engage the upper ends of pins 42 and urge said pinsdownwardly against the resistance of spring urged ball 49 and seal 62.

It will be understood that the position of disks 45 relative to pins 42may be adjusted so that all heads 23 function-in identically the samemanner to subject all cans to the same test. However, it is well knownin the industry that variations in atmospheric conditions will changethe operation of pins 42 so that a further adjustment to suit differentatmospheric conditions is desirable. However, inasmuch as a change inatmospheric conditions will affect all heads 23 equally I provide meansfor shifting the position of switch 52 and its actuating pin.

Switch 52 is preferably secured to the underside of a generallyhorizontally disposed radially extending plate 75 which is fastened atits inner end to the underside of arm 31 by means of bolt 76 and nut 77;both arm 31 and plate 75 being apertured to receive bolt 76therethrough. A yieldable washer 78 of fiber or the like is interposedbetweenplate 75 and arm 31 adjacent bolt 76 so as to permit limitedmovement of the opposite outer end of plate 75 and still hold switchsupport plate 75 against shifting under vibration.

The outer end of plate 75 is urged downwardly at all times by a leafspring 79 and said plate and arm 31 are spaced apart by the shank of abolt 80 which ispassed through a hole in arm 31 and threadedly engages atapped hole in plate 75. A downwardly projecting boss 81 may be formedrigid with the underside of plate 75 so as to permit the tapped hole inplate 75 to be extended to a sufficient length.

By rotating bolt 80 it will be obvious that plate 75 may be swungslightly upwardly or downwardly to shift the position of switchactuating pin 53 as desired.

Bolt 80 may therefore be employed to alter the efiective action of pin42 when changes in atmospheric conditions make such an alterationdesirable.

By the invention herein described the testing and rejecting operationsneed not slow down the movement of the cans and said operations may becarried out at any desired speed.

It should be noted that the pole pieces 57, 58 of the electromagnet 56offer no resistance to rotation of the rejected cans with the resultthat very little friction between the supports 2 and cans 24 is requiredto cause the cans to roll on the pole pieces 57, 58.

Although the device would operate satisfactorily if the can engagingsurfaces of the pole pieces 57, 58 were of a different shape than thatshown, it is preferable that the can engaging surfaces be circular. Inthis manner, the cans roll on the pole pieces and little or noresistance to such rolling is olfered.

I claim:

1. In a can handling system: a conveyor having supporting means formoving vacuum packed cans along a horizontal path of travel in onedirection with the tops of said cans horizontal, means for moving saidcans vertically toward and away from a testing position during saidmovement, an electromagnet positioned alongside the cans in said path,an electrical circuit including a stationary switch and the winding ofsaid electromagnet for energizing the same, means cooperating with saidcans at said testing position for successively applying suctionexternally to the tops of said cans for urging said tops upwardly, andmeans responsive to the upward movement of said tops for actuating saidswitch to close said circuit when the vacuum in any one can is less thana predetermined amount and said one can is at a point in said pathalongside said magnet whereby a defectively packed can is attracted tosaid magnet, said magnet being formed with a can engaging surfaceinclined to said path so that urging of said one can in said directionby said supporting means will move said one can laterally 01f said pathof travel, means for conveying such a rejected can away from said path,and means for opening said circuit before the next succeeding can isalongside said switch.

2. In a can handling system: a conveyor having supporting means formoving vacuum packed cans along a horizontal path of travel in onedirection with the tops of said cans horizontal, means for moving saidcans vertically toward and away from a testing position during saidmovement, an electromagnet positioned alongside the cans in said path,an electrical circuit including the winding of said electromagnet forenergizing the same, means cooperating with said cans at said testingposition for successively applying suction externally to the tops ofsaid cans for urging said tops upwardly, vertically disposed gageelements carried by said conveyor and respectively positioned above thecans in said path, said elements being supported for movement from anormal lower position to an upper position under the urging of said topswhen said suction is applied thereto, whereby a gage element is moved tosaid upper position when engaged by the top of a defectively packed can,stationary switch means adjacent said path and actuatable by saidelements when the latter are in said upper position for closing saidcircuit and energizing said magnet whereby a defectively packed can isattracted to said magnet, said rejecting cans having less than apredetermined vacuum therein, means for supporting cans for movementalong a predetermined horizontal path of travel with the axes of saidcan vertical, means for moving said cans vertically toward and away froma testing position during said movement, a stationary electromagnetpositioned alongside but spaced laterally from the cans in said .path, aunitary electrical circuit including a coil in said magnet forenergizing the latter, means cooperating with said cans at said testingposition and actuatable by a defective can for closing said circuit whensuch defective can is alongside said magnet whereby a defective can isattracted to said magnet and held thereto, said magnet being providedwith a can engaging surface angularly disposed relative to said pathwhereby movement of a defective can by said supporting means will causesuch can to be rolled along said can engaging surface to a position withits axis offset from said path and means for opening said circuit whensaid can is in said last mentioned position before the next succeedingcan cooperates with said circuit closing means.

4. In a rejection system for vacuum packed cans for rejecting canshaving less than a predetermined vacuum therein, means for supportingcans for movement along a predetermined horizontal path of travel withthe axes of said cans vertical, means for moving said cans verticallytoward and away from a testing position during said movement, astationary electromagnet positioned alongside but spaced laterally fromthe cans in said path, a unitary electrical circuit including a coil insaid magnet for energizing the latter, means cooperating with said cansat said testing position and actuatable by a defective can for closingsaid circuit when such defective can is alongside said magnet whereby adefective can is attracted to said magnet and held thereto, said magnetbeing provided with a can engaging surface angularly disposed relativeto said path whereby movement of a defective can by said supportingmeans will cause such can to be rolled along said can engaging surfaceto a position with its axis offset from said path, a stationary memberalongside said can supporting means and including an upper edge adaptedto partially support said can when the latter is moved to saidlastmentioned position with said can partially supported on said supportingmeans, and means for opening said circuit before the next succeeding cancooperates with said circuit closing means when the center of gravity ofsaid can passes said edge whereby said can is overbalanced when theattraction of said electromagnet is arrested.

5. In a rejection system for vacuum packed cans for rejecting canshaving less than a predetermined vacuum therein, means for supportingcans for movement along a predetermined horizontal path of travel withthe axes of said cans vertical, a stationary electromagnet posif tionedalongside but space laterally from the cans said path, a unitaryelectrical circuit including a co'il i'n said magnet for energizing thelatter, means actuatable by a defective can for closing said circuitwhen such defective can is alongside said magnetwhereby a defective canis attracted to said magnet and held thereto, said magnet being providedwith an arcuate can engaging surface substantially tangent to said pathat one point thereof and progressively more inclined to said path in adirection away from said point whereby movement of a defective can bysaid supporting means will causevsuch can to be rolled along saidarcuate surface from said one point to a position with its axisspacedradially outwardly of said path, and means for opening said circuit whensaid can is in said last mentioned position. I

6. In a can handling system including a conveyor having supporting meansfor moving vacuum packed cans in single file along a horizontal path oftravel with their axes vertical, a plurality of suction heads carried bysaid conveyor and respectively adapted to apply suction externally ofthe tops of said cans means 'for successively moving said cans into andout of engagement with said heads, vertically movable elementsrespectively carried by said heads and movable by the tops ofdefectively packed cans from a normal lower position to an upperposition When said suction is applied, a stationary switch supportedalongside a point on said path and switch actuating members carried bythe upper ends of said elements respectively for actuating said switchwhen said elements are in said upper position, electrically actu atedejecting means alongside said path for ejecting a defectively packed canfrom said path, an electrical circuit including said switch and ejectingmeans for actuating the latter when said switch is closed by one of saidmembers. V

7. In acan handling system including a conveyor having supporting meansfor moving vacuum packed cans in single file along a horizontal path oftravel with their axes vertical, a plurality of suction heads carried bysaid conveyor and respectively adapted to apply suction externally ofthe tops of said cans means for successively moving said cans into andout of engagement with said heads, vertically movable elementsrespectively carried by said heads and movable by the tops ofdefectively packed cans from a normal lower positionfto an upperposltion when said suction is applied, a stationary switch supportedalongside a point on said path and switch actu ating members carried bythe upp'erends of said elements respectively for actuating said switchwhen said elements are in said upper position, a stationaryelectromagnet positioned alongside said point of said path, anelectrical circuit including said switch and the winding of saidelectromagnet for energizing said electromagnet when said switch isengaged by one of said rnembe'rswhereby a defective can at said point isattracted to said electro magnet, said electromagnet being provided witha can engaging surface inclinded to said path of travel and along whicha defective can'may roll during movement of such can on said supportingmeans foiurging such can to a position with its axis offset from saidpath.

References Cited in the file of this patent UNITED STATES PATENTS2,093,429 Foss Sept. 21, 1937 ,526 Cummings Dec. 1, 1942 2, 70,485Rieber Oct. 9 1951 8 Watson Nov. 24, 1953 2,8 1,300 Rofinger et al. Jan.28, 1958 MA -m

